Lake structures (23rd of April 2010)

Lake. No people or birds. Peace. One can hear only a quiet buzz. Gentle vibrations of the water surface around the
structures... It sounds scary when I tell it this way, the image does not convey the full message. It is perhaps
better that way.

From year 2002 until year 2005, I was researching mostly carbon nanotubes, especially the gas interacting with them.
Namely, somebody got the idea that carbon nanotube materials could be used to efficiently story gases, especially
hydrogen. The idea is not completely nuts because these materials are very porous and the graphite surface
attracts hydrogen. But, on the basis of some of my quantum calculations that you can download e.g.
HERE, I found out that the idea is not likely to become
reality. In any case, I got hooked on the geometry of a cylinder, so I thought about how the carbon nanotubes
covered by monoatomic layer would look like. Such a "protection" could be performed e.g. to improve the chemical
or mechanical properties of an individual nanotube. The results of my study can be found in
THIS paper, and one of the figures from the paper is shown
below.

The figure shows how the cylinder surface can be covered with spheres in many different ways (the number of
(energetically) favorable ways depends on the ratio of radii of sphere and cylinder). The three structures that I've
chosen for the "artistic realization" are also mutually different with respect to the symmetry of the arrangement of
spheres on the cylinder. I found out later that such structures are no rarity in biology. Thus, e.g., a similar
symmetry can be found in microtubules,
bacterial flagellae, but also pineapples (!, see below).

Sometime at the end of year 2003 I held a lecture on the meeting of Croatian physical society entitled
From carbon nanotubes to pineapples or something like that. I know that for many this was, to put it
mildly, weird.

It is interesting that the symmetry of the structures can be described by only two integers and that the structures
are not periodic in the direction along the cylinder axis. Of course, I immediately got the idea for the image and
that is how the image that opened this post was made. I recently returned to the project and made several more
images. Here's one below.

And here is one from the year 2003, the first or the second one that I made (below). And that's it for this post.